Antibacterials

Question 1

Prophylaxis for rheumatic fever

Answer 1

Phenoxymethylpenicillin or sulfadiazine.

Question 2

Invasive group A streptococcal infection: prevention of secondary cases

Answer 2

Phenoxymethylpenicillin.

Patients who are penicillin allergic, either azithromycin [unlicensed use] or clarithromycin [unlicensed use] or erythromycin (in pregnancy or within 28 days of giving birth).

Question 3

Meningococcal meningitis: prevention of secondary cases

Answer 3

Ciprofloxacin or rifampicin or i/m ceftriaxone [unlicensed indication].

Question 4

Haemophilus influenzae type b infection: prevention of secondary disease

Answer 4

Rifampicin;

Alternative if rifampicin unsuitable: ceftriaxone [unlicensed] (based on limited evidence), or oral ciprofloxacin [unlicensed] or azithromycin [unlicensed] (however effectiveness in healthy individuals has not been determined).

Question 5

Diphtheria: prevention of secondary cases

Answer 5

Azithromycin or clarithromycin;

Alternative if more easily administered: intramuscular benzylpenicillin sodium.

Question 6

Pertussis, antibacterial prophylaxis

Answer 6

Clarithromycin (or azithromycin or erythromycin).

Question 7

Pneumococcal infection in asplenia or in patients with sickle-cell disease, antibacterial prophylaxis

Answer 7

Phenoxymethylpenicillin.

If penicillin-allergic, erythromycin.

Question 8

Orthopaedic surgery, antibacterial prophylaxis

1. Joint replacement including hip and knee

Answer 8

Single dose of i/v cefuroxime alone

or i/v flucloxacillin + i/v gentamicin

Question 9

Orthopaedic surgery, antibacterial prophylaxis

2. Closed fractures

Answer 9

Single dose of i/v cefuroxime or i/v flucloxacillin

Question 10

Orthopaedic surgery, antibacterial prophylaxis

3. Open fractures

Answer 10

Use i/v co-amoxiclav alone or

i/v cefuroxime + i/v metronidazole

Question 11

PROM prevention of intra-uterine infection

Answer 11

Erythromycin.

Question 12

Penicillins MOA

Answer 12

Beta-lactam antibiotics that inhibit bacterial cell wall synthesis

prevents cross linking of peptidoglycans

Question 13

Why can flucloxacillin by used in infections caused by beta lactamase producing bacteria?

Answer 13

Beta-lactamase stable

Question 14

When is benzylpenicilin commonly used

Answer 14

Prehospital in meningococcal disease

Question 15

When is Pen V (phenoxymethylpenicillin) commonly used / 1st line

Answer 15

Streptococcal tonsilitis

Question 16

When is flucloxacillin commonly used / 1st line?

Answer 16

Impetigo
Cellulitis
Mastitis
Osteomyelitis
Septic arthritis

Question 17

When is Amoxicillin commonly used / 1st line?

Answer 17

CAP (low - mod severity)
Exacerbations of chronic bronchitis
Acute otitis media
Acute sinusitis
Oral infections

Question 18

Cephalosporins MOA

Answer 18

Broad spectrum beta-latam antibiotics

Attach to penicillin binding proteins to interrupt cell wall synthesis

Question 19

Cefalexin usually taken via?

Answer 19

Mouth

Question 20

Cephalosporins

1st gen

2nd gen

3rd gen

Answer 20

Cefalexin

Cefuroxime

Cefotaxime and ceftriaxone

Question 21

Tetracyclines MOA

Answer 21

Inhibit protein synthesis

Question 22

Which tetracycline may be used in malaria prophylaxis?

Answer 22

Doxycycline

Question 23

Tetracyclines are tx of choice for which conditions?

Answer 23

Chlamydia
Lyme disease

Question 24

MOA of aminoglycosides

Answer 24

Interfere with bacterial protein synthesis

Question 25

When is gentamicin contraindicated

Answer 25

Myasthenia gravis

Question 26

Gentamicin monitoring

Answer 26

Take peak (1hr after dose) and trough (pre next dose) If trough is high, increase interval between doses If peak is high, decrease the dose

Question 27

Macrolides MOA

Answer 27

Inhibit protein synthesis

Question 28

Main use for fusidic acid

Answer 28

Primarily topically for minor staphylococcal skin / eye infection

Question 29

Max length of fusidic acid course length

Answer 29

10 days

Question 30

Why is chloramphenicol rarely used systemically?

Answer 30

Serious adverse effects Aplastic anaemia Peripheral neuropathy Optic neuritis

Question 31

For how long after healing should chloramphenicol be used to tx bacterial eye infections?

Answer 31

48HRS

Question 32

MOA of vancoymycin

Answer 32

Glycopeptide abx, inhibits peptidoglycan formation Therefore acts against GRAM +VE (anaerobic and aerobic)

Question 33

Cautions for vancomycin

Answer 33

Hx of deafness Caution in the elderly

Question 34

When is vancomycin given orally?

Answer 34

C. diff colitis

Question 35

MOA of metronidazole

Answer 35

Bacterial nucleic acid synthesis inhibitor High activity against anaerobic and protozoa

Question 36

Co-trimoxazole =

Answer 36

Trimethoprim and sulfamethoxazole

Question 37

Contraindication for trimethoprim

Answer 37

Any blood disorder (dyscrasis)

Question 38

If trimethoprim is used during pregnancy what should be px alongside it?

Answer 38

5mg folic acid daily